Felt run arrangement



United States Patent FELT RUN ARRANGEMENT Edward D. Beachler, Beloit, Wis, assignor to B'eloit Iron Works, Beloit, Wis., a corporation of Wisconsin Application March 16, 1956, Serial No. 572,131

3' Claims. (Cl. 34-117) This invention relates to a dryer section arrangement for paper machines, and more particularly, to an improved felt arrangement for paper machine dryer sections.

In the usual paper machine dryer section, there are provided a plurality of tiers of paper dryer rolls. Ordinarily only an upper tier and a lower tier are provided with. a plurality of parallerly aligned rolls in each tier. The rolls or drums provide a shell which is heated. internally with steam and which is freely rotatable. The paper weaves a serpentine path through the dryer passing beneath a first roll in the lower tier then over a first roll in the upper tier, and then back down beneath-the second roll in the lower tier, etc. pass over the tops of each of the rolls in the upper tier so as to engage the paper web during most of its travel on such rolls and thus control and assist in removal of moisture from the web. There are also provided traveling looped lower felts trained over the bottoms of the rolls in the lower tier so as to cover the paper Web during most of its travel on the rolls of the lower tier. In the present high speed paper machines, the dryer section is so long that more than one upper felt and more than one lower felt are required in each case. In such instance, a first upper felt will cover the tops of a first plurality of rolls in the upper tier and then be directed away from the upper tier of rolls; and a second upper felt will cover a second plurality of dryer rolls in this tier in'nnediately adjacent to the first plurality. The second felt is directed by guide means from a felt dryer to the first of the plurality of rolls which this felt covers in the tier. This occurs at the so-called break in the upper felts (where one felt is directed away fromthe last roll of one plurality or group of rolls and the second felt is directed toward the first roll in the next group of rolls).

At higher paper machine speeds, however, it has been noticed that a disproportionately great number of breaks occur in the web in the region of the so-called' felt break. The instant invention is based upon not only the discovery of the causes for such breaks in the web,- but also the discovery of means for overcoming this difficulty. I

Heretofore, the felt at the felt break which was moving intoward the tier of rolls turned to produce a pumping: effect, in that it carried along a substantial amount of air therewith. This air was-apparently forced. into a chamber defined in part by unsupported stretches of paper webextendingbetween the dryer drums. The force of the air against the unsupported stretches oflp'aper web is now believed to be the cause for" the excessive number ofbreaks in the web in this region:

The instant invention is based in part upon the discovery that the pumping elfect of a traveling felt moving toward the dryer drum can be neutralized by an oppositely moving felt coming away' from the dryer drums and which is positioned in close-running relationship to the first felt and substantially parallel thereto. This felt.

arrangement results in a substantial neutralization or the pumping effect and, in fact, eliminates substantially any Upper traveling looped felts shown only partially).

2,909,848 Patented Oct. 27, 1959 movement of air in the direction of the felt traveling toward the dryer section.

It is, therefore, an important object of the instant invention to provide an improved felt arrangement for the dryer section.

It is a further object of the instant invention toprovide an improved felt arrangement which eliminates undesirable air flow at a break in the felts between paper machine sections running at different speeds.

Yet another object of the instant invention is to provide a felt arrangement wherein felts moving toward and away from the dryer drums are mounted in closerunning generally parallel relationship so as to neutralize the pumping efifects of either.

Other and further objects, features and advantages of the present invention will become apparent to those skilled. in the art from the following detail disclosure thereof and. the drawings attached hereto and made a part hereof.

On the drawings;

Figure 1 is essentially a diagrammatic view of a paper machine dryer section showing the prior art arrangement; and

Figure 2v is essentially a diagrammatic arrangement of a paper machine dryer section. embodying the instant invention.

As shown on the drawings:

In Fig. 1, a paper machine dryer section of the prior art, indicated generally by the reference numeral 10, comprises an upper tier of dryer rolls 21, 22, 23 and 24, and a lower tier of dryer rolls 31, 32, 33, 34 and 35 (some The direction of travel of the rolls in each case is indicated by an arrow; and it will be appreciated that a paper web W lapped about each of the rolls 21, 22, etc. and 31, 32, etc.. travels in the direction indicated by the rotation of the rolls. A first upper felt 40 passes under a guide roll 41, over a web covered top surface region of the roll 21, under another guide roll 42, over the top web covered surface of dryer roll 22', around another guide roll 43 and then away from" A felt 44, however, carries with it a substantial amount of air at the rapid speed at which the felt 44 is traveling and this air is forced into a chamber C defined by adjacent top rolls 22 and 23, a bottom roll 33 and unsupported reaches of the web x and y. This results in the application of additional stretching forces, for example, against the unsupported Webreach x.

In. like manner, a first bottom felt 59' guided by guide rolls 51 52 and 53 is urged against the bottom on web covered surface regions of the first group of bot-torn rolls 31', 32 and 33 and the felt 50 is then directed away from the bottom tier. A second felt 54 guided by guide rolls 56- and 57 is urged against the bottom web covered portions of the next group of bottom rolls 34 and 35. The

upwardly directed run 54a of the second bottom felt 54 Since the individual felt dryers (not shown) for, for

Z3 example, the lower felts 50 and 54 are ordinarily spaced apart a substantial distance, the usual practice heretofore has been to direct the off running first felt run 50a and the oncoming second felt run 54a in opposite directions, as here shown. This has been the usual paper machine arrangement for years.

Referring now to Fig. 2, which shows a dryer section 1% embodying the instant invention, it will be noted that the upper tier of the dryer section 100 comprises a first plurality of rolls 121 and 122 and a second plurality of rolls 123 and 124 immediately thereadjacent in the upper tier. Each of the rolls 121, 122, 123 and 124 has a top paper web covered surface region as indicated by the travel of the web W over each of the rolls 121, etc. The direction of the rotation of the rolls 121, etc. is indicated by arrows. A first felt 140 is directed by guide rolls 141, 142, 143 and 143a so as to be urged against the top web covered region of each of the rolls 121 and 122. As the felt 140 is taken off the roll 122 by the guide roll 143, it is then directed by the position of the guide roll 143a in a straight felt run 140a from which it goes on back to the felt dryer (not shown).

A second felt 144 is mounted on guide rolls 145, 145a, 146 and 147 so as to be urged against the top web covered region of each of the second plurality of rolls 123 and 124. In addition, the guide rolls 145 and 145a guide the oncoming felt 144 in a straight felt run 144a as the felt 144 approaches the first roll 123 of the plurality of rolls 123 and 124. Ordinarily, the felt run 144a would tend to pump a substantial amount of air in its direction of travel and between the rolls 122 and 123. However, it will be noted that the oncoming felt run 144a is mounted in close-running generally parallel relationship with the off running felt run 140a. In general, the guide rolls 143 and 145 must be spaced apart at least about one inch in order to operate effectively and preferably the guide rolls 143 and 145 should not be spaced apart more than about six inches (i.e. should not space the felt runs 1411a and 144a more than six inches apart).

The alignment of the felt runs 1411a and 144a with respect to the traveling distance in which they are parallel and the distance which they are spaced apart involves merely the arrangement of such runs 1413a and 144a so as to prevent pumping of air in either direction. In particular, the function of the off running felt run 140a is that of neutralizing the pumping effect of the oncoming run 14402. For this purpose, the off running felt run 1411a should be at least about one half as long as the oncoming felt run 144a and is preferably of substantially the same length. The neutralizing effect of the off running felt run 140a can of course be increased by moving this felt run 140a closer to the oncoming felt run 144a, and for this reason it is not absolutely necessary to have the off running run 1411a of the same length as the oncoming run 144a.

Referring now to the lower tier in the dryer section 100, it will be seen that this comprises a first plurality of rolls 131 and 132, a second plurality of rolls 134 and 135, and a single dryer roll 133 between the first and second pluralities of rolls, with all of the rolls mounted in the same (lower) tier. A first lower felt 150 is directed by guide rolls 151, 152 and 153 so that the felt 150 is urged against the bottom web covered region of each of the first plurality of rolls 131 and 132. Means in the form of the guide rolls 152 and 153 are also provided for directing the felt 15% away from the roll 132 along a straight felt run 156a extending from between the rolls 132 and 133. The felt run 1513a actually is directed downwardly at an incline in close running relationship to a bottom portion 133:: of the roll 133. As indicated the paper web W covers a surface region of the roll 133 having an angular dimension B, and the felt run 15011 is directed in close-running relationship to a surface portion 133a of the web covered surface region (B) of the roll 133.

The felt run 150a continues away from the roll 133 in a downward incline until it turns about the guide roll 153. This particular arrangement has the advantage that the roll 132 may be driven at a different speed from the speed of the roll 133. The same is true of the rolls 122 and 123 in the upper tier. In addition, the particular incline of felt run 150a permits convenient disposal of the paper web during start-up of the dryer section 100.

A second lower felt 154 is directed by guide rolls 155, 156, 157, 158 and 159 so as to urge the felt 154 against each of the bottom web covered regions of the second plurality of rolls 134 and 135. In addition, the guide rolls 156 and 157 urge the felt 154 against a second portion 13315 of the web covered surface region of the single roll 133. The portions 133a and 13% of the web covered region of the roll 133 are, of course, peripherally spaced from each other. In this way, it will be seen that a considerable amount of the pumping effect of the felt 154 is dissipated by the cooperation between the off running felt run 150a and the traveling first portion 133a of the roll 133 in close-running relationship therewith. Both the rotating roll 133 and the felt run 1511a are moving in a direction opposed to the movement of air which would be pumped by the felt 154.

The guide rolls 155 and 156 direct the felt 154 in a straight run 154a which is in generally parallel closerunning relationship with the off running felt run 150a. As will be appreciated, the cooperation between the felt runs 150a and 154a is the same as the cooperation between the felt runs a and 144a above described. In this respect additional reduction in the pumping effect of the oncoming felt run 154a is accomplished.

It is important to note, however, that the pumping effect of the oncoming felt run 154a may be reduced or neutralized to some extent by both the cooperation between the dryer 133 and the felt run a and the cooperation between the felt runs 150a and 154a, although both are preferably used. In addition, a tendency for warm air to rise from the basement into the dryer section 100 is neutralized by this arrangement.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a paper machine dryer section, a first dryer roll, a second dryer roll immediately thereadjacent, each roll having a traveling paper Web covered surface region, a first felt urged against the web covered region of said first roll, first guide means directing said first felt away from said first roll and along a first inclined felt 11m extending from between said first and second rolls, a second felt urged against the web covered region of said second roll and second guide means directing said second felt along a second inclined felt run toward said second roll, said first and second felt runs being in substantially parallel close running relation so that each felt counteracts the tendency for the other felt to pump air in its direction of travel, said felt runs being spaced apart 1 to 6 inches.

2. In a paper machine dryer section, a first plurality of rolls mounted in one tier, a second plurality of rolls mounted in said tier, a single dryer roll in said tier between the first and second pluralities of rolls, each roll having a paper web covered surface region, a first felt urged against the web covered region of each of said first plurality of rolls and then directed in a first felt run in spaced close-running relationship to said single roll away from said tier, and a second felt directed on a second felt run in close-running parallel relationship to said first felt run toward said tier and urged against the web covered region of said single roll and of each of said second plurality of rolls.

3. In a paper machine dryer section, a first dryer roll, a second dryer roll immediately thereadjacent, each roll having a traveling paper web covered surface region, first and second guide rolls in closely spaced relation mounted between said dryer rolls, a first felt urged against the Web covered region of said first roll and over the first guide roll and away from said dryer rolls, a second felt directed in parallel close running relation to said first felt 5 as it approaches said second guide roll and then directed over the guide roll and urged against the web covered region of the second dryer roll, a third dryer roll positioned between and beneath the first and second dryer rolls having a surface region thereof covered by the paper web, a third felt directed in close running relationship to a first position of said surface region of the third dryer roll and then in a first felt run away from said third dryer roll, and a fourth felt directed in a second felt run in close running generally parallel relationship to said first felt run and then onto a second portion of said surface region of the third dryer roll.

References Cited in the file of this patent UNITED STATES PATENTS 1,595,482 Minton Aug. 10, 1926 10 2,433,122 Hornbostel Dec. 23, 1947 FOREIGN PATENTS 728,756 Germany Dec. 3, 1942 

